Inventory management or delivery management of products are performed by attaching a wireless tag and a sensor onto products. The wireless tags include an integrated circuit (IC) tag, a radio frequency identification (RFID) tag, etc. The wireless tag typically stores an ID (identification) of each product. The sensor is a temperature sensor or a global positioning system (GPS) sensor, for example. By monitoring the wireless tag and the sensor, the type of a product and environment information (temperature information, position information or the like) may be retrieved. With the wireless tag and the temperature sensor, the time for the management of products is saved, and human errors in the management are prevented.
For example, Japanese Unexamined Patent Application Publication No. 2004-315154 discusses a technique for managing a product using a wireless tag. In accordance with Japanese Unexamined Patent Application Publication No. 2004-315154, a temperature sensor, or a temperature sensor and a shock sensor are attached to a packaging container to make sure that the product has not suffered from extremes of temperature change or shock. Japanese Unexamined Patent Application Publication No. 2005-314073 discusses a product management technique in which a temperature sensor is attached to each product and a container holding the product. Japanese Unexamined Patent Application Publication No. 2005-228268 discusses another product management technique in which information read from a wireless tag and a sensor is successively stored such that an amount of data of the stored data is prevented from becoming too large.